How to design a complex grading plant without tears

摘要

Brunner Mond has recently started up a new 90kt/y plant for producing the range of grades of Refined Sodium Bicarbonate required by our customers. However, during the early days of commissioning, the screening section of the plant consistently failed to achieve the specific throughputs and separation efficiencies observed during test-work with the equipment manufacturers. The feedstock to the new plant is pneumatically conveyed and air-classified using a rotating disc device prior to screening. Relative humidities in the new plant building are very low, particularly inside the screen decks. Pneumatic handling, coupled with the low humidity, led to severe problems with electrostatic charging which had not been evident during design trials. The problem has been partially resolved by reconfiguring the screen decks in a manner that raises the relative humidity; work to increase the humidity further is due to commence shortly.